Power tools such as radial arm and table saws are used extensively in the construction industry. In the use of such tools, there is often the need to accurately position the end of a piece of material, such as lumber and the like, relative to the blade of the saw so that a cut can be made to size the material to the desired length. In the past, numerous fences and other gauging devices have been used to so position the end of materials relative to the cutting blade of the tool. Such devices range from the most basic fence including the permanent attachment of a block a specified distance from the blade of the cutting tool against which the end of the material to be cut is butted prior to cutting, to more sophisticated adjustable fences such as those shown in U.S. Pat. Nos. 2,485,274 to R. G. Garrett; 2,492,686 to W. H. Cummins; 2,747,625 to S. N. Small; 2,779,366 to E. A. Snow; 2,890,729 to J. M. Horn; and 3,391,717 to D. G. Melin.
Although these patents disclose a range of adjustable saw fences, each of these devices represents an overly complex unit which is difficult and expensive to produce and in many cases difficult to use. For example, U.S. Pat. Nos. 2,890,729 and 2,485,274 do not provide unlimited positioning of the workpiece to be cut, but rather provide incremental adjustments only. The apparatus disclosed in U.S. Pat. Nos. 3,391,717 and 2,747,625 disclose units having a movable fence attached to the measuring tape such that the tape expands or retracts as the fence is moved. Further, although these devices provide a rail on which the fence slides, the construction of the fence assembly and its attachment to the rail does not provide an optimum operating relationship.
Similarly, U.S. Pat. Nos. 2,779,306 and 2,492,686 provide fences which translate on a fixed rail. However, these units also fail to provide an optimum structure and relationship between the fence assembly and the rails on which they operate.
Therefore, a need exists for an infinitely adjustable cutting tool fence which is both easy to operate and maintain and simple in construction such that the cost and maintenance of the unit are minimized.